Master gyroscope system



Aug. 12, "1952 Filed March 22, 1946 c:. NORDEN ET AL 2,606,448

MASTER GYROSCOPE SYSTEM 8 Sheets-Sheet l Aug. 12, 1952 c. NORDEN ET AL 2,606,448

MASTER GYROSCOPE SYSTEM Filed March 22, 1946 a Sheets-Sheet 2 12, 1952 c. NORDEN ET AL 2,606,448

MASTER GYROSCOPE SYSTEM Filed March 22, 1946 8 Sheets-Sheet 3 g- 1952 c. NORDEN ET, AL MASTER GYROSCOPE SYSTEM 8 sheets-sheen:

Filed .iaarch 22, 1946 Aug. 12, 1952 c. L. NORDEN ETAL MASTER GYROSCOPE SYSTEM 8 sheds-sheet 5 Filed. March 22. 1946 1952 c. L. NORDEN ET AL V 2,606,448

MASTER GYROSCOPE SYSTEM Filed March 22 1946 s Sheets-Sheet s Aug. 12, 1952 C. L. NORDEN ETAL MASTER GYROSCOPE SYSTEM Filed March 22, 1946 8 Sheets-Sheet 7 Aug. 12, 1952 c. NORDEN ET AL MASTER GYROSCOPE SYSTEM 8 Sheets-Sheet 8 Filed March 22, 1946 Patented Aug. 12, 1952 MASTER. oynosoors SYSTEM Carl L. Noreen, New York, and, William c, Coulourn,,'M eo a, a snors t Th was Laboratories Corporation, New York, N, Y -a corporation of Connecticut epp iqationMar 22, 46., Seria a. am,-

Ou in nt on, re a s: to a a ter y o o e. system and'more part u a ly to h ch i adapted tov providefa" stabilized platform upon which may bemounted; an azimuth gyroscope and from which any deviation about the vertical or yaw axis, the transverseor pitch axis, and the longitudinal or roll a 'iSQOf a craft. such as an aircraft, vessel, orthe like, may be.,meas ured.

In the pr r "a t; azi u h s r sqop that is gyroscopesfadapted toIindicate the direction in which the] plane wasQtraveling were mounted by a, suspension system; in which the vertical axis was, rigid with thefainplane; Due, to precession of the gyroscope w hen the plane would climb or dive or when the plane, rolled about, alongitudinal axis, as, in ban r a t rn, errors, Were troduced, Then too, the, relative: motion between the, airplane, andthe, Carda'n. ring of the gyro.- scope. had to be transmitted toaniridicating ins ru'men t rough a ppropriate, fo owp y tem This requ ed, work which. uc d further forces; tending to precess the azimuth 9; Claims. (01. re -5.34)

gvroscope mmoitsvset dire ion, E en i Otw l ctric, l wu s s em: were. us d. th r ction m ther yroscope whe l, and it s spension ea n s. is o mal ylsuf ci nt o, ca se. precession Then, tea. pr c ss on is u ed. y he r a o the earth and by movement he p ane ab t the earth, The amount of precession'furthermore varies in difierent latitudes. An airplane is a. h gh y maneuv ra le e el. n s t n c an e n tti u e nd'i s a e ratio n d celeration in flight make it extremely difiicult to devise a gyroscopic system, which will indicate true direction at all time .9 that it canbe used for navigational purposes as well as to control surveying cameras, fire control apparatus, bombsight equipment, and an automatic pilot;

One object of our inventionis to provide a master gyroscopic system which will provide a stabilized platform upon which is mounted an azimuth gyroscope which may be used to indicate the true direction inwhieh the plane is: flying at all times 7 7 I I Another objeotpt ourinvention is'to provide a stabilized platform which is always normal to a line drawn through the center of the earth from the position of the plane or' vessel and from which deviations of the craft aboutei ther the longitudinal or transverse axis thereof may be measured. i

Another object or our invention is to provide a master gyroscopic system which may be used to control an aircrafts automatic'pil'ot, b-ombe sight equipment, fire. control apparatus, photo-F graphic surveyequipment, and the like,

Another object, of our a stabilized platformfwhich will be maintained normal to a line, drawn through the center of the earth irrespective of the attitude, course, speed, or latitude. ofethe plane.

Another object of our invention is to provide a. stabilized platform whiohwill remain ina position normal to a line drawn through the. center of the earth, irrespective of the. maneuvers. of the plane and the acceleration or deceleration of the plane.

Another object ofour invention is to provide a novel means for processing a gyroscopic system.

Another object of our invention is to provide a gyroscopic"systemwhich willfdeliver considerable and usable torque about the axes of control so that follow-up systems. such as synchronous transmitters may beoperated by the movement of the stable platform ream-[veto theyessellwithe out, introducing precession errors,

, Other and further objectsof our invention will appear from the following description.

In. generaLour invention contemplates the provision o fj a fplatfolini upon which are mounted three gyroscopes,'each of which has a restrained axis, perpendicularto the axis of control of the respective eyrose pef The stabilized platform is maintained perpendicular a line drawn through the center of thejearth, irrespective of the movement of the craft upon which it is mounted. Upon the stable platform is mounted an azimuth gyroscope, Deviations of the. aircraft about its roll or longitudinal axis are detected and me'asuredfby the change in angular relationship betweenthe stabilized platform, Carda n ring and the main housing, Deviations in pitch fthe aircraft are detected and measured by the change in the angular relationship between the stabilized platform and'the Cardan ring ,"about the herilzontally stabiliZed 11 1 91 or transverse axis. 'Deviationsof the aircraft in yaw or course are measured about a true vertical; axis and not the aircrafts normal vertical axis,.d ue to. the a t .t eti e az muth. arenas mou e n the stable platform. These deviations are used to actuate thetransmitters of synchronous systems and can be used to control equipment of any size or Weight by suitable servomotors. For example,

a complete gen platform may be stabilized by means of our-gyroscopic system sothat the problems of naval gunnery may be greatly simplified, irrespective of the pitch and roll of'a naval vessel. "Slmilarly; gun platforms on airplanes, as well as platforms for mountingae'rial cameras,

may be stabilized"regardlessofthepitch and roll i pf the? airplanes? Navigational instruments,

nve i s o rovi e bombsights, or automatic pilots may be controlled from a gyroscopic system of our invention.

We provide means for always maintaining the pitch gyroscope and the roll gyroscope with their axes of spin along a line drawn through the center of the earth, together with means for maintaining the stabilized platform normal to the axes of spin of the pitch and roll gyroscopes.

We provide means for locking erecting mechanisms during periods of acceleration and deceleration when centrifugal force or other forces would adversely affect the erecting mechanisms. Either constantly or only during the periods when the gravity erecting mechanisms are rendered inoperative, we provide magnetic means for precessing the gyroscopes to compensate for the change in latitude, the rotation of the earth, and the component of speed in the east-west direction which would alter the effect of the precession due to the rotation of the earth. In this manner, the stabilized platform is always maintained normal to a line drawn through the center of the earth and the azimuth gyroscope will al ways maintain a set direction. If this set direction be north, the azimuth gyroscope will act as a gyroscopic compass. The set direction, however, may be any desired direction, as for example the desired course on which the plane is to fly, thus making the instrument useful, not only for navigation but also for blind flying and the like.

In the accompanying drawings, which form part of the instant specification and which are to be read in conjunction therewith, and in which like numerals are used to indicate like parts in the various views:

Fig. 1 is a diagrammatic perspective view of a master gyroscopic system showing one embodiment of our invention.

Fig. 2 is a top plan view of a gyroscopic sys- Igem which is diagrammatically illustrated in Fig. 3 is a view of the upper portion of the system shown in Fig. 2, but drawn on an enlarged sca e.

Fig. 4 is a sectional View drawn on an enlarged scale taken along the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary sectional view taken on the line 5--5 of Fig. 4.

Fig. 6 is a fragmentary sectional view taken on the line 6-6 of Fig. 4.

Fig. 7 is a sectional view drawn on an enlarged scale taken on the line 'I! of Fig. 2.

Fig. 8 is a sectional View taken on the line 88 of Fig. 7 drawn on an enlarged scale.

Fig. 9 is a sectional view taken on the line 9-9 of Fig. 7.

Fig. .10 is a sectional view drawn on an enlarged scale taken on the line I-I0 of Fig. 2.

Fig. 11 is a sectional view taken on the line III I of Fig. 10.

Fig. 12 is a fragmentary side elevation taken on the line I2I 2of Fig. 11.

Fig. 13 is a sectional view taken on the line I3I3 of Fig. 3.

Fig. 14 is a sectional view taken on the line I I-I4 of Fig. 13.

Fig. -15 is a sectional view on an enlarged scale taken along the line ll 5 of Fig. 13.

Fig. 1 6 is a sectional view taken along the line I6-|6 of Fig. 3.

Fig. 17 is a sectional view taken along the line II--I'I of Fig. 16.

Fig. 18 is a detailed sectional view with parts broken away; taken along the line I8--I 8 of Fig. 4.

Fig. 19 is a diagrammatic view showing the electrical connections used in our system.

Referring now to the drawings, and particularly Fig. 1, the stabilized platform I is mounted on a Cardanic suspension. A gimbal ring 2 is pivotally mounted for rotation about a longitudinal or roll axis by means of fore and aft shafts 3 journaled in bearings 4 rigidly carried by members 5 which are immovably secured in any desired manner to the airplane or vessel supporting our gyroscopic system. The supports 5 are shown to be perpendicular, but it is to be understood their direction is immaterial. They may be suspended from an overhead point or extend laterally, The gimbal ring 2 is free to turn 360 degrees in the bearings 4. Bearings 6 extend transversely of the gimbal ring 2 along a line perpendicular to the longitudinal or roll axis of the craft on which our gyroscopic system is mounted. Shafts I are journaled in the bearings 6 and permit the stable platform I to rotate through 360'degrees. Three gyroscopes are mounted on the platform I. The gyroscope wheel 8 is mounted to spin about an axis which is parallel to the platform I. For purposes of convenience, each of the gyroscopes will be described by reference to its spin axis, that is, the axis of rotation of the gyroscope wheel; its control axis, that is, the axis around which the gyroscope exercises control, and the tilt axis, which is the axis perpendicular both to the spin axis and thecontrol axis. In the case of the gyroscope 8, the spin axis is horizontal. The control axis is normal to the stable platform I, and the tilt axis extends at right angles to the control axis and the spin axis, and is also parallel to the plane of the stable platform I. The ring 9 represents the housing of the gyroscope 8. It .is'pivotally mounted about the tilt axis in a Cardan ring I9. A shaft II is pivotally mounted in a framework I2 which is part of the stable platform I. The shaft is rigid with the ring III, which turns therewith in upper bearing l3 and lower bearing I4 mounted on the framework I2. Secured to the shaft II for rotation therewith is a gear wheel I5 which meshes with a pinion I6 which is secured to a shaft IT for rotation therewith. The shaft I1 is adapted to be driven by a servomotor I8. A gear wheel I9 is keyed to the shaft II and rotates therewith. The gear I9 meshes with a pinion 20 mounted to rotate shaft-2| of the synchronous transmitter 22. The pinion 20 is meshed with a gear wheel 23 adapted to rotate shaft 24 of the synchronous transmitter 25. The Cardan ring I0 carries a member 26 made of Swedish iron adapted to be influenced magnetically by either pole 21 or pole 28 of a pair of electromagnets to precess the gyroscope, as will be hereinafter more fully pointed out. The gyroscope housing 9 carries a wiper 29 adapted to contact conducting segments 30 mounted on the Cardan ring II]. The segments 30 are separated by suitable insulation. The contact of the wiper 29 with the upper segment 39 is adapted to rotate the servomotor I8 in one direction, while contact of the wiping element 29 with a lower segment 30 is adapted to rotate the servomotor I8 in the opposite direction, as will be hereinafter more fully pointed out.

A gyroscope 3| is adapted to rotate about an axis normal to the platform I in a housing represented by the ring 32. The housing 32 is pivoted to rotate in bearings carried by the stable platform I around an axis which extends fore and aft of the craft. The axis is represented by the shaft. 33; which ri d. w ththe heesina 3 c nd is: adaptedzto; otate: therewith Thasheft. 33.- ca ies an iron. member 4 secure to, the sh ft 33 for rotatio he e ith. w i h ro me b r: a pted to be influenced lternately br t e oles 3.5; and 36; of electromagnets to process the gyro; scope 3|. The y osc pe 3: is dapted to con.- trol the stable platform around the pitch or lateral axis.v The axis. 3-3,;is; at right; angles to the shaft 31,. which isin the direction of the spin axis, and at; rig-ht angles to the transverse axis of the vessel and is therefore the tilt axis. of the pitch gyroscope. wheel 35]. Parallel to the con-.v trol axisof the pitch yroscope we. mount a bail 38 for pivotal movement. about a line parallelto. the pitch axis. The bail 3.8. is; really an inverted pendulum. Its upper end is. formed with a slot 39 in which the axle 3,1 is. adapted, to. rotate. Tilting of the. bail will cause movement between a side of the slot 39 and the axle. 31: and will create. a torque. about the tilt axis 33:. Secured to the. bail 38 is a member 40 adapted to co=actwith a locking pin 4] which is actuated by an electromagnet- 42. The locking pin 4|, together with member 40., is adapted to immobolize the ball 38. A pair of conducting segments 43. and 44, similar to the twosegments 3.0 of 'the azimuth gyroscope assembly, is mounted on an insulating member- 45 carried by thestabilized' platform. A conducting arm or wiper 46 is adapted to make. contact with either segment 44 or segment 43 upon rotation of the gyro-housing about the tilt axis 33. Contact between thewiper 48 and the segment 44 is adapted to rotate the servornotor 41 in one direction, While contact of the wiper 46 with the segment 43 is adapted to rotate theservomotor 41 in the opposite direction. The servomotor shaft 48 carries a gear Wheel 49 which meshes with a gear wheel 5.0. The gear wheel 59 is rigidly secured to theibeare ing 6. carried by the gimbal ring 2. The construction is such that rotation of the gear wheel 49 in a clockwise direction will rotate the sta bilized platform l around the lateral or pitch axis in a clockwise direction as viewed from the left or port.

A gyroscope is mounted on; an axle 52 likewise normal to the stable platform l and parallel to the axle 31. The housing of the gyroscope wheel 5! is represented by the ring 5.3 and is mounted to rotate around an, axis lying in a vertical plane parallel to the lateral or pitch axis of the. craft. It will be noted that. this d-irection is at right angles to the direction around which the. housing 32 of the pitch" gyroscope is mounted. The axis of rotation of the gyrohousing 53 is represented by the shaft 54 which is rigidly secured to the housing 53 and adaptedto rotate therewith in suitable bearings carried by the stable platform I;- The shaft 54 carries for rotation therewith: a member 55' made of soft iron or any other suitable ferrous material adapted to be influenced alternately by the pole 56 of an electromagnet or the pole 5-1 of another electromagnet to precess the gyroscope. The gyroscope 5! controls the stabilization of; the platform I caused byrotation around the longitudinal or roll axis and will be referred to for purposes of convenience as, the roll gyroscope. The control axis of the roll gyroscope 5!. extends fore and aft parallel to the vertical plane including shafts 5'! and 58, around which we pivot a ball 59. The ball 59 is formedwi-th a slot 69 in which the axle 52 of the gyroscope 5| is lodged. Actually the speed ofrotation of he; erroseene heels 3 .v and: th s oo great for re druse. in. our erecting y ems hat wha s.- shown n t e. di gram c v 1 be a per nent t axles nd 5 tim ots 39 and; 69 re. c ual. prac ic memb iv by the gyroscope wheels in the same direction of rotation as the gy scope wheels, as will be hereinafter more fully pointed out. Tilting of the bail, which is, really an inverted pendulum, lodges one sidev or the other of slot 60 against the rotating axle. 52. and createsa torque. around the tilting axis of the gyroscope, causing presess o to he ertica as w e a t r more fully pointedout. Actually, the axles 31 and 2$ a alway p ra le a d. a a s p in o rd thelzenith The. platform I is always parallel to the true horizon, 'whateyermay be the. location of he craft o rryinsour s abi z d. y ose pi t m i re pec t e e h he r s o e hous ng 53 carr es a ont a m r w e E adapted; to make contact alternately with a p ir: o se m 2; nd, .3 m nt d, n an insulating member; 64'. Contact of the wiper arm 6| with segment 63 is adapted to rotate the servomotor 6 4 in one. direction, while contact of the wiper 51 with the segment 52 is.

adapted to rotate. the servomotor 64' in the. opposite direction. They servomotor 54 is provided with a shaft 65 to which is keyed a pinion 66, meshing with a gear 61. The. gear filis rigidly mounted on. the bearing 4 so that rotation of the ear 66 in a clockwise direction will rotate the; gimbal ring 2 in a clockwise. direction and hence the stabilized platform I in a clockwise direction, viewed from aft. A gear 68. is carried by the gimbal ring 2 and meshes with a pinion 7 13 carried by a shaft 74 of asynchronous trans-.

mitter 15 which is mounted in a bracket 16 carried by the. stabilized p latf onm, Rotation of the stabilized platform around a fore and aft, or roll axis will be reflected bythe. rotation of the rotor of the syrwhronous. transmitter H. Rotation of thestabilized platform I. around the transverse or-pitch axis will .bereflected by the. rotation of the rotor of "the synchronous transmitter 1.5. The, ball 59v ofithe rol1 gyro-. scope 5| carries a, member 'lfi adapted'to coactwith a locking pin 1], actuated by an electroma net 1.8. Upon energiaation of the electromagnet 18 the pin T! will seat, in the member 75 to immobilize the bailv 5 9 7 Referring now to F 2; thestabilized platform is shown as, a framework IBI, which is mounted for rotation about the pitch axis in suitable. bearings carried in the gimbal ring [02. The, gimbal ring IE2 is mounted for rotation around a fore and aft axis in bearings carried by a, member H15, which member is rigidly rie in any ita em nner by h c t s pporting our master gyroscopio system. The azimuth gyroscope housing [09 carries a" wiper 1.29 adapted to contact segments I30 carried by the Cardan H0. 'Ifhef rame; H 2 carries a suitablebearing l ,l3 in which the shaft I H is adapted to rotate. The C'ardan Illl carries a'gear H5 adapted to be driven by a servdmotor indicated generally by the reference numeral H8. The housing [3-2 of the pitch gyroscope is mounted in bearings for rotation about: an axis normally parallel to a vertical plane including the longitudinal axis of the crafti It carries a wiper blade I46 adapted to contact segments I43 and I44 carried by the insulating member I45. A core of soft iron I34 is positioned-for influence by either of solenoids I36 or I31. The bail I33 carries a member I40 adapted to lock the bail in association with locking pin I4I, actuated by electromagnet I42. The roll gyroscope is mounted to rotate in a housing I53, which is pivoted for rotation in suitable bearings around an axis nonmally perpendicular to a vertical plane including the roll or fore and aftaxis of the craft. The housing carries a wiper IBI adapted to make contact with segments IE2 or I63 carried by an insulating member I64 suitably supported by the stabilized platform IOI. Secured to the roll gyroscope housing I53 is a bracket carrying a member I55-of ferrous material adapted to be influenced by solenoids I51 and I58 to tilt the gyroscope housing, as will be hereinafter more fully described. The bail I59 is pivoted about a fore and aft axis and carries a member I16 adapted to co-act with a locking pin I11 when influenced by the electromagnet I18. A gear wheel I12 is secured to the gimbal I02 and rotates therewith. The gear I12 meshes with the gear I13, which drives the rotor of the synchronous transmitter I15. The servomotor, indicated generally by the reference numeral I41, is adapted to rotate pinions which mesh with the gear I50, which is carried rigidly secured to the gimbal I02, as will be hereinafter more fully described. A gear I61 is carried by the supporting framework I and corresponds to the gear 61 shown in Fig. l. The servomotor and the synchronous transmitter associated with the mechanism for rotating it about the fore and aft axis and for transmitting relative rotation around the longitudinal axis, is omitted for purposes of clarity. The servomotor, however, is of the same general construction as the servomotors which will be described in connection with rotation around the azimuth axis and. for rotation about the pitch axis.

Referring now to Fig. 4, the gimbal ring H32 supports the stabilized platform IOI for rotation about a transverse axis. The bearings for the gyro-housings for the pitch and roll gyroscopes are shown in Fig. 4. They comprise a member having a squared end I80 suitably clamped on the stabilized platform IOI and carrying a ball bearing I8I. around which the gyro-housing is adapted to pivot. Referring now-to the pitch gyroscope in Fig. 4,. there'is secured to the gyrohousing I32 by suitable screws I82, a sleeve I83 of any suitable material. Secured to the sleeve are pole pieces I84 and I85, which carry windings I86 and I81. The gyroscope wheel I3I is secured to the shaft I88. The armature winding I89 of the motor rotates between the pole pieces I84 and I85. The armature of the gyroscope is provided with a commutator I90 against which suitable brushes I9I contact. It willbe noted that the motor shaft rotates in suitable ball bearings. Referring now to the roll gyroscope, there is a similar. sleeve I83. adapted to support pole pieces I85 and field windingsv I81. The armature I89 is provided with a commutator I90, against which suitable brushes I9I and I92 contact to supply the armature current. The upper ends of the motor shafts of both the roll and pitch gyroscopes are provided with a cap member I93. The cap member I93 engages a'friction disk I94. The friction disk is secured to a shaft I95 against the upper end of which a spring clip I96 acts, The spring pressureinsures proper frictional contact between the friction disk I94 and the cap member I93. Secured to the shaft I for rotation therewith is a gear sleeve I91 which meshes with a gear I98 rotatably mounted on a stub shaft I99. A cork sleeve 200 is integrally carried by and rotates with the gear I98 and is adapted to contact the slot formed in the bail I59. For purposes of convenience, the reference numerals on the transmissions for both the roll and pitch gyroscopes are the same, since the structures are identical. It will be observed that the transmission just described is such that the sleeves 200 of both the roll and pitch gyroscopes will rotate in the same directions as the gyroscope wheels. For example, suppose the roll gyroscope were rotating in a clockwise direction, as viewed in Fig. 4 from above. The friction disk I94 would rotate in a counter-clockwise direction. The sleeve gear I91 would likewise rotate in a counter-clockwise direction, rotating the gear I98 in a clockwise direction, and hence the shaft I99 and the bushing 200 in a clockwise direction, which was the direction of rotation assumed for the gyroscope wheel I5I. The same relationship will hold true for the pitch gyroscope, so that the simplified arrangement shown in Fig. 1 holds true. The effect of the transmission, however, is to greatly reduce the speed at which the cork sleeves rotate and thereby increases the life of the cork friction sleeves and minimizes the adverse effects of any run-out or unbalance of the cork sleeves and gears I98. The bails I38 and I59 are pivotally mounted so as to act as inverted pendulums. By reference to Figs. 4 and 18, it will be observed that the lower end of the bails are forked and are mounted about suitable ball bearings I54, suitably supported from the stable platform IOI. A pivoted member I4Ia is adapted to carry the bail locking pin I4I. A spring I4Ib normally urges the bail locking support member I4Ia upwardly against a stop I4Ic. The action of the bail locking solenoid I42 is to move the bail locking member I4Ia downwardly against the action of the spring I4Ib. In Fig. 4, the gear I50 supported by the gimbal ring I02, and the gear I12 supported by the gimbal I02, are clearly shown.

Referring now to Fig. 3, there is shown the upper portion of Fig. 2 on an enlarged scale. The reference numerals used in Fig. 3 correspond to thoseused in Fig. 2 and are one hundred more than those used for corresponding parts in Fig. 1. The gimbal I02 carries the stabilized platform IOI. The azimuth gyroscope housing I09 is pivoted to rotate about a horizontal axis in the Cardan ring H0. The wiper element I29 makes the contact with the segments I30. The large gear H5 is carried by the Cardan ring IIO. The azimuth gyroscope servomotor is indicated generally by the reference numeral H8 and it will be more fully described hereinafter. Meshing with the gear I I5 is the gear I I 9, which drives a pinion I20, which rotates the rotor of the synchronous transmitter I22. The gear II9 carries a smaller gear II9c which meshes with a gear I23, which rotates the shaft I24 of the synchronous transmitter I25. The gear I12 is carried by the gimbal ring I 02, which meshes with the gear I13 carried by the shaft I 14, to which is secured the rotor of a synchronous transmitter I15 adapted to transmit rotation about the lateral or pitch axis. The servomotor for applying torques to the stable platform ghee-gee ing H3 and a lower hearing I M, in which bearings the Cardan ring H is pivoted. The g yroscope housing ['09 is adapted to rotate about a horizontal axis in bearings-"carried by the Cardan ring H0. The lower end of the Cardan ring H0 carries an iron member I26 adapted to be acted upon by electromagnets I21 and 1-28 to precess the azimuth gyroscope. v The large gear 9 carried by the Cardan ring -I'|lfm'eshes with the gear H9 and drives the gearin'g described with reference to -Fig. 3ito drive the synchronous transmitters H2 and 125. w I

In Fig; 8 the bearing '1 I3 is shown in fd'etail. A plurality of copper rings 'I03fare shown, through which the electrical connections are made. The wiring may pass downwardly through 'the'tube This'is merely a'detail of constructionin one embodiment of ourinvention. v

Further details of the-azimuth gyroscope con. struction are shown in-Figs. 10, 11, andl'2. .It will be noted that the'niethodj"ofspinning the azimuth gyroscope wheel I'Qiiiin'the azimuth gyrohousing ['99 is 'simi la'rto that described in connection with the roll an'd ipitc'h "gyros'eo'p'es. fThe gyro-housing, however, is' pivoted in the .Cardan ring I it instead of on thest'able platform directly.

The wiper arm I29 -is carried by "an insulating block I29 mounted'on thegyrohou ing' [09. The conducting segments I30 and anf'are mounted on an insulating block I30a, 'eerrieabythe-carden ring Hi1. M I,

Referring now to FigsB "and'13to rrmelusite, the servomotor' construction "'c'a'nbe readily seen. The armature shaftof a'in'otor 30ll' c'arries a pinion 'Siii which mesheswith a gear'suz, secured to a shaft etc, to whi'chisfin tum'seeureu a bevel gear tea. The bevel eeer'so meshestvith a bevel gear 3195 secured to a shaft 303,371 ch' 'eerrieeepimen St for rotatiohth'lwith. frnep'imon 3D! meshes with a'gear'3ll8 which in turn'ine'she's with a gear see.- The gears" 3'0 and 3'09,"it'wi'l1 "be observed, willtherefore rotate'iinfopp'osi'te directions. Re- 'ferring now to FigJIi'the-"gear 3091s pressed on and rotates with a bushing 3 0, which is journa led "around the end 3 l -of-sliaft :31'4. Th'e bushing 3| 0 has axial play along the share-31min normally held to the right'b'y thei'action of a spring spider are. A clutch plateau is's'eciired to a shaft3 4 rotating in a bearing' 3'|5. The end ofthe-shaft has secured thereto a "p'mientle which meshes Withfthe gear I50f'which i's c'arriedby the gimbal ring E82. The clutch .plate'3l 3 is normally unclutched from the "gear 3119, and is with a cork ring 3H. Aneletio'mag'net or solenoid 318 is adapted to attractj'an armature 3|$ normally held in the position showfififi 15 thro}1gl 1 the action o'fasprin'g'32n. When'the winding of the solenoid 3|8 is energized, the armature 3l9 will be attracted, forcing it to pivot about pivot pin 32| to cam the bushing 3|0 tothe, lett, as viewed in Fig. 15, agaihstthe action of the spring spider arms 3 i 2. This bringsthe'rotating gear 309 into engagement with the clutchplate 3| 3 an d applies a torque tendingt'o rotate. theishaft iill to which the clutch plate '313 "is ecures. 7 This torque is transmitted by the'shaft' 3|; to the pinion 316.

Since the pinion "3 1'6 isfr'io'uiited iipon the stable ":platform l0|, "the"torque applied to pinion 31 t is transmitted to thest'ableplatform through reaction upon gear I 50 secured" to "the 'gimbal ring I 02. This "is diagrammatically shown in Fig. 1 as I the interaction between gear 49' and gear 50.

The gear 30 8 shown in *Fig, 13 is adapted to applya torque toa pinion 322 which in turn applies atorgue to the stable platform in the opposite direction. I

The gear 302showninFigs. 3, 13 and 16, meshes with agear-323, whichis'adapted to rotate a shaft 324 towhich'issecured-apinion 325. The pinion 325 r'neshes withfa gear 326, which is in turn meshed with another gear 32'l The gears 326 and 32lfaire similar to the gearsj308and 309. They are adapted to be alternately clutched to pinions 323 "and 32 9, ftvhichare in mesh with the ring gear lit, which is earried by the Cardan'ring no of the "azimuth gyroscope. A solenoid33ll'is adapted to contr'ol't he {clutchingof the gear 326 to the pinion "328. v A sol'enoid "33-| is adapted'to control the clutching of the pinion $29 to the gear 321. -Fig. 17 showsthe solenoid arrangement which is similar to that described with respect to Fig. '15. The armature 332 is normally held in non-actuati'ng position by the'action ofa spring 333. The armature is pivoted about'a pivot pin 334 so that upon energization of theflwind ing of the electromagnet 331, the armature 332 will rotate in a clockwise direction to clutch gear 321 to the clutch plate 335 to rotate pinion 329 and thus apply a torque to the ring gear l5. This torque produces precession of the azimuthgyroscope about its tilt bearings until the wiper I29 is returned to the mica neutral I30. v

The servomotor systemshown in Figs. 13 and 15 is controlled by the wiper arm MB. A similar serv'omotor system, adapted to "act through gear |61 to apply a torque to the gimbal ring I02 about the longitudinal axis is controlled by the wiper a'rm |6|,shown in Figs. 2 and 6.

The electrical connections are shown in Fig. 19, which will be described hereinafter.

The operation of our device can be best understood by reference to the diagrammatic view shown in Fig. 1. It will be assumed the gyroscope wheels 3| and 5| are spinning in a clockwise direction, viewed from above. It will be assumed that in the figure the twogyrosc'ope wheels 3| and 5| are on the after 'or'rea'rward part of the stable platform I and that the azimuth gyroscope wheel 8 is mounted on the forward part of the platform I. The transverse'or pitch axi'sextehd's from port to "starboard, that is, from left to right. The servomotor 41 is 'mount'edon the port side of the platform. The servomotor 64 is mounted on the after part of the gimbal ring Z. It will be further assumed that the gyroscope wheel 8 is revolving in a clockwise direction, as viewed from port. These directions must'be kept in mindif the correct sequence of motions, which will be described in connection with the operation of our instrument, is to be understood. Itis to be understood further that either direction of rotation for each ofthe gyroscope wheels may be chosen, as the directions of rotation of the 'gyr'oscopes do not affect the theorybf operation. Let us assume that the gyroscope wheels are all spinning in the direction just pointed out and that the spin axes of the gyroscope wheels3l and 5| are vertical and aligned with gravity, that is, pointing toward the center of the earth. Let us assume further that the platform I is stabilized so that it is normal to the-direction of the spin axes of the gyroscopes 3| and 5|. Let us further suppose that the inaww '11 strument is mounted inari aircraft which is flying directly north from vthelso'uth. Let the airplane now make a left climbing turn, and'let usconsider the effect ofthisfirst upon the mechanism which exercises control aroundthelongitudinal'axis of coritroL' Since the pane mustbank" port side downwardly in making 'a left turn, the port side of the platform I, due to the friction'ofthe fore and aft bearings of the gimbal r n 'z; will tend to move downwardly along with the port side of the airplane. In other words, there will be a tendency for the stabilized platform I to rotate in a counter-clockwise direction around the fore and. aft axis. When this. occurs, a torque will be applied to the roll gyroscope wheel in a counterclockwise direction around its control axis, that is, around a fore and aft axis. This will cause the top of th'gyrosco'pe axl'52 to precess forwardly,

thus moving'the wiper 6| off the neutral point of the segment 64, ontoth'e conducting-segment 62. This willcomplete a circuit which tends to rotate the servomotor pinion 66 in a clockwise direction, thus applying a torque to the gimbal ring 2 in a clockwise direction and through bearing 1 to the stable platform and thence to the roll gyroscope wheel. This torque is of sufficient magnitude to overcome the original disturbing counter-clockwise torque produced when the port wing went down, and also to precess the top of axle 52 of the'gyroscope wheel 5] 'r'earwardly, bringing the wiper arm 6! back to neutral position. v

In climbing, the plane nose will move upwardly and the after end of the plane will move downwardly, that is, there will be a rotation around the lateral or pitch axis. Due' the friction of the bearings and the friction in connection with driving the synchronous transmitter rotor, the after end of stable platform! will tend to move downwardly along with the after end of the airplane. When this occurs, a' clockwise torque is exercised around the control axis of the gyroscope 3|. This clockwise torque 'will precess the top of the axle 31 to port, thus carryin'gthe wiper 46 off of its neutralpointon the insulating block 46 and on the conducting segment 44. This will energize the servomotor to" produce a counter-clockwise rotation of the pinion 49, thus rotating the stable platform"! ina counter-clockwise direction; The counterfclockwise rotation of the platform-"l will cause the top of the axle 31 to precess to starboard, thus carrying the wiper 49 back to the neutral point when: the platform I has reached a position normal to gravity around a transverse axis. It will be seen that'during the turn, the platform is maintained in a horizontal position, both with respect to rotation around the pitch axis and the roll axis. As the plane turns to the left, a counter-clockwise torque, viewed from above, is applied to' the gyroscope 8 about its vertical or control axis. This torque arises from the friction of the parts and the connections to the synchronous transmitters, which are connected to the gear [9. The counter-clockwise torque about the vertical axis will precess the port side of the gyroscope housing downwardly, the rotation of the housing being about a fore and aft axis in; a'counter-clockwise direction, viewed from astermthus carrying the wiper blade downwardly and onto conducting segment 30'. This energizes the correct solenoid to rotate the servomotor l8 in'a counter-clockwise direction, as viewed from above, thusrotating shaft I! and gear ['5 in a counter-clockwise direction. This will rotate gear l5 in a clockwise direction, thus precessing the gyroscope 8 in a clockwise direction; viewed fromaft around a fore jand aft axis, and raising the port side of the housing and hence the wiper blade 29, bringing the wiper 'blade to neutral position when the cardan 10 again is aligned -w ith the original plane of orientation around the vertical axis.

Let us now assume as before that the ship is headed north in straight, level flight. The earth is rotating from west to east at a speed of nine hundred nautical miles per hour. Since the spin axis of the roll gyroscope 5| tends to remain stationary in space, this motion of the earth, the plane being carried along with the earth through the forces of gravitation, will causev the ball 59 in effect to tilt to port, that is, the gravity of the earth will exercise-pull upon the inverted pendulum and since the spinaxis is inclined to port, the weight of the bail slotupon the upper portion of the rotating axle will cause a counter-clockwise torque around the tilt axis, that is, the transverse axis of the gyroscope 5|. it being remembered that the gyroscope is rotating'in' a'clockwise direction, as viewed from above. This causes the top of the roll gyroscope axle 52 to precess to starboard, thus rotating the gimbal ring 2 in a clockwise direction. This carries the wiper 46 of the pitch gyroscope to port, contacting the segment 44 and energizing the servomotor 41 to rotate the gear 49 in a counter-clockwise direction. This counter-clockwise rotation of the gear 9 will rotate the stabilized platform in a counter-clockwise direction, thus precessing the pitch gyroscope to starboard, along with and parallel to the precession of the top of l the roll gyroscope axle 52 to starboard. The precession of the top of the roll gyroscope axle 52 to starboard realigns the bail 59 withv the pull of gravity.

The precession of the top of the roll gyroscope to starboard with the consequent rotation of the stabilized platform in a clockwise direction will produce a clockwisetorque around the tilt axis of the pitch gyroscope 3 I. This clockwise torque around the tilt axis of the pitch gyroscope will precess the top 31 of the pitch gyroscope axle aft, thus tilting the ball 38 aft. Since the pitch gyroscope is rotating in a clockwise direction, this will produce a counter-clockwise torque around the tilt axis of the pitch gyroscope and again precess it forwardly, cancelling the effect of the aft precession of the top of the pitch gyroscope 'due to the clockwise rotation of the stable platform.

It will be seen that the effect of the rotation of the earth is automatically compensated for by the ball 59 when the'ship is headed on north course. When the ship is headed on an east and west course, the bail 38 will compensate for the rotation of the earth. .If the'ship is headed toward the east, the speed of the plane accelerates the action just described. If the ship is headed on'a westerly course, the action just described is minimized by the difference between the speed of the airplane and the speed of the rotation of the earth. At intermediate courses, both bails are affected, each taking care of the components along the respective control axes of the pitch and roll gyroscopes. v

Let us now observe the effect of the speed of the airplane in a northerly direction as it has an effect upon the change in latitude. As the ship heads north, the speed of travel tends to bring the upper end of the axle 31 of the pitch gyroscope to a position inclined rearwardly with respect to the vertical. The effect of this is to tilt the ball 38 aft, thus bringing the upper side of conductor 4I3, through segment I62, through conductor 4I4, through the winding 4I5 of the servomotor controlling the application of torque to the stable platform around a fore and aft axis. When the wiper I6I is in contact with conducting segment I63, current will flow through conductor 4I6, through the winding M1 01 the electromagnet controlling the opposite clutch of the servomotor indicated generally by the reference numeral 64 in Figs. 1 and 19. The servomotor is of the same general construction as the ones heretofore described in connection with the azimuth and pitch gyroscopes. A motor armature 4I8 drives a pinion 4I9, which is meshed with a gear 426, which is in turn meshed with another gear 42I, so. that the gears 420 and 42I rotate in opposite directions. Clutch members 422 and 423 are adapted to be operated by the electromagnets 4 I 1 and4 I 5 to clutch pinlons 425 and 424 alternately to the gear I61, which is carried by the support I05. Rotation of the pinions 424 and 425will rotate the gimbal ring I02 around a fore and aft axis.

The bail locking magnet I42, which is adapted to lock the bail of the pitch gyroscope, is supplied with electrical potential from the battery through I conductor 406 and conductor 426. Normally current will not flow through the bail locking magnet since the circuit through conductor 421 to ground 435 is interrupted. The magnetic precession solenoids I36 and I31 are supplied potential from the-computer 428. The computer is an instrument, which is not part of the present invention, into which the course of the craft is set by knob 429 and appears at window 430. If desired, the course may be set automatically from a synchronous repeater. The speed of the craft is set by knob 43I and appears at window 432. This likewise'can be set automatically from a synchronous repeater actuated from a speed meter. The latitude is set by a knob 433 and appears at window 434. This likewise can be set automatically by means of a synchronous transmitter. It will be observed that the synchronous repeaters operated by our stable platform will always keep the platform normal to a line drawn through the center of the earth around both the pitch and roll axes .Our azimuth gyroscope will always indicate any desired direction and also operate synchronous transmitters. The synchronous transmitters along the three axes can be used to operate synchronous repeaters to control servomotors and stabilize a second platform exactly in accordance with the stabilization of our master platform. In addition, the stabilized platform can be suspended in a Cardanic suspension and oriented always to the north. The platform then will always indicate the true horizon, that is, it'will be parallel to the plane of the true horizon, no matter where the craft happens to be on the earth. We can orient the second stabilized platform always to the north by setting the Cardan ring of. the azimuth gyroscope initially in a'northerly plane, and it will always maintain a northerly direction. On the oriented stabilized repeater platform, we can mount a gyroscope similar to the azimuth gyroscope. Its spin axis, however, will be perpendicular to the stabilized platform when the airplane is at the Equator, and parallel to the stabilized platform when the airplane is over the pole. In other words, the Cardan ring of the gyroscope mounted on the second stabilized platform has its axis parallel to the 'axis ofthe earth through the North and South Poles. Asthe airplane moves about in space, the angle between the plane of the second stable platform and the Cardan ring will measure the angle of elevation of the pole above the horizon. Since the altitude of the elevated pole, that is, its angle above the horizon, is equal to latitude, the gyroscope mounted on the second stabilized platform will always measure latitude. A synchronous transmitter may operate a synchronous repeater to keep latitude set in the computer automatically. The computer generates a voltage which is a function of the speed of rotation of the earth. This is corrected by the component in an east or west direction of the speed of the craft and its direction of flight. The component in a north and south direction generated by the speed and course of the craft makes corrections in a latitude which is set in event the latitude gyroscope system is not used. Correct signals are produced and applied, not only to the precession solenoids I36 and I31 of the pitch gyroscope, but also to precession solenoids I56 and I51 of the roll gyroscope. The currents which flow when the circuits are completed through the precession solenoids produce effects equivalent to the efiect described above of the bails 38 and 59. The potential applied, however, has no effect until circuits are completed through the precession solenoids.

An inverted pendulum 428 is mounted to pivot about a line parallel to pitch axis of the craft. The pendulum is connected to conductor 421 and is adapted to complete the circuit through ball locking electromagnet I42 and the precession soleof contact points 436 or 450. Centering springs 433 normally hold the inverted pendulum out of contact with either of the contact points 450 or 436. A switch 45I through which the circuit of the precession magnets I36 and I31 is adapted to be completed is normally connected to the ground 452. In this way, the pitch gyroscope is precessed to compensate for the rotation of the earth and changes in latitude and components of speed, both in latitude and in longitude, by the output of the computer. This anticipates or duplicates the work normally done by the bail 38 of the pitch gyroscope. For this reason, if we operate with the computer always cut in, we may use a lighter bail since it will have to do less work than otherwise. Should the computer fail or if we desire, the switch 45I may be moved into contact point 453. In such case, the pitch bail will make the corrections, except in maneuvers which produce an undue fore and aft acceleration. In such cases, the circuit, both through the bail locking electromagnet I42 and the precession solenoids I36 and I31 will be completed through conductor 421, through the inverted pendulum 428, to ground 435. A similar inverted pendulum 429 is mounted along a fore and aft axis and is provided with centering springs 454. It is adapted to complete the circuit through bail locking electromagnet I18, through ground 438, upon undue acceleration or deceleration in a transverse direction. A switch 455, which is normally adapted to complete the circuits through precession solenoids I56 and I51, through ground 430, may be moved to make contact with contact point 466 so that both the bail locking electromagnet I18 and the precession solenoids I 56 and I 51 may have their circuits completed through the pendulum 429 and ground 438. The precession solenoids I56 and I51 make the same corrections which are made by the action of the bail 59 of the roll gyroscope. By always applying the correction, as is the case when switch 455 is groundseat-43o, we may make the bail lighter than we otherwise could, thereby reducing the erection rate of the bail and improving accuracy of (obtaining the vertical. Whenever the acceleration around the roll axis becomes great enough to overcome the effect of the centering springs l5 i, the bail locking el'ectromagnet' H8 is immediately energized, locking the bail and permitting the correction to be made only magnetically through the action of the computer 528 and the s'olen'oid's i 56 and an.

While we have describedfor -.purposes of illustrati'on the use of inverted pendulumsan'd centor-ing springs for controlling the bail locking mag-nets, and if desired the precession magnets as'well, it Will be understood that any other suitable means responsive to acceleration, such as rate .gyro'sc'opes, may be employed. As soon as the acceleration or deceleration has ceased, that is, when a m'aneuver' is completed, the bails 38 and -58 are unlocked and may again exercise control. s

Current is supplied from conductor till to --a motor l i l, whicli'drives alternatort lfand supplies single phase alternating current tothe conductors-Wdfi and 54%. The synchronous transmitters comprise devices having bi-polar rotors and Y-wound stators. The single phase alternating current is supplied to the rotor-s. The synchronous repeaters are similar devices having their rotors connected in parallel with therotors of the transmitters and the stators connected in parallel with the stators of the transmitters. The rotor 22 is the rotor of one of the azimuth synchronous transmitters. The rotor 25 is the rotor of the other'az'imuth synchronous transmitter. The gear is drives gears 29 and 23,as"can be seen by reference to Figs. 1 and 19. Similarly, the gear 13 is driven from the gear l2 to rotate the rotor l5 of the pitch synchronous transmitter. Thef'geartfi rotates the geariiiwhich drives the rotor ll jo'f the roll synchronous transmitter. The rotor 22a will follow the movements of the rotor '22. The rotor flfi'a'v'vill follow the movements ofthe rotor 25. The'rot'o'r War Will renew themovements of'the rotor T5, and the rotor Ha will follow the movements of the rotor 1-1. As many repeaters as maybe desired may be operated from 'a single transmitter by connecting them in parallel with "the transmitter. transmitter rotorrn'ay be'usedto operate a foll'owup system'or relays to control servomotors which maybe used to operate any desired'instrumentality. For example, a synchronous repeater may be operated from the pitch gyroscope to keep the plane in level flight while the output of the azimuth repeaters may be used to control the rudder of the plane. The roll-gyroscope repeater may be used to operate the ailerons. The "synchronous transmitters-may be used to stabilize a gun platform on a ship, which gun platform is always maintained parallel to the plane of the horizon. They may be used to operate fire control instruments or a bombsight.

It will be seen that we have accomplished the objects of our invention. We have provided a master gyroscopic system which will provide a stabilized platform upon which may be mounted an azimuth gyroscope for use in indicating true direction, and may therefore be used as a navigational compass and in connection with blind flying. We have provided a master gyroscope system which will provide a stabilized platform which is always oriented in the plane of the horizon, irrespective of deviations in course,

The

speed, 0r"-attitude of the craft. Wehaveprovided a master gyroscope system which maybe used to control an aircrafts automatic pilot, bombsight equipment, fire control apparatus, photographic survey equipment, and the like. We have provided a stabilized platform which will always be oriented in the plane of the horizon, irrespective of maneuvers of the plane and the acceleration and deceleration of the-plane. We have provided a master gyroscopic system which will deliver considerable and usable torque about the various axes of control so that follow-up-systems may be operated by the movement of the stable platform relative to the vessel. The azimuth gyroscope in our system is unaffected by bank turns, as has been the case in previous installations.

It will be understood that certain features and sub-combinations are of utility and'may'beemployed Without reference to other features and sub-combinations. Thisis contemplated byand is within the-scopeof the claims. It is further obvious that various changes may be made in details within the scope of the claims without departing from the spirit of the invention. It is, therefore, to be understood that this invention is not to be limited to the specific details shown and described.

Having thus described our invention, we' claim:

1. A master gyroscope system, including in combination, a craft, a support, means for suspendingsaid support for rotation relative to said craft about both a predetermined longitudinal axis and about a predetermined transverse axis, means'preventing rotation of said support relative to said craft about a vertical axis, affirst' prime mover for applyingtorqueto said support about said longitudinal axis, a second prime mover for applying torque to said support about said transverse axis, a first gyroscope having a vertical spin axis carried by said support for movement about a't'ransverse axis, a second 'gyro.-. scope having a vertical spin axis carried by said support for movement about a longitudinal axis, means responsive to relative movement between said'first gyroscope and said supportfor controlling said first prime mover, and means responsive to relative movement of said second gyroscope and said support for controlling said second prime mover.

2.'A master gyroscope system as in claim '1, including in combination an azimuth gyroscope supported by said support, said azimuth gyroscope being carried by a Cardan ring, and means for mounting said Cardan ring for rotation about an axis normal to said support.

3. A master gyroscope system, including in combination a platform, means for suspending said platform for rotation only about both a longitudinal axis and about a transverse axis, a first prime mover for applying torque to said platform about said longitudinal axis, a second prime mover for applying torque to said platform about said transvers axis, a first gyroscope having its spin axis in a plane normal to said platform carried by said platform for movement about a transverse axis, a second gyroscope having a spin axis in a plane normal to said platform carried by said platform for movement about a longtiudinal axis, means responsive to relative movement between said first gyroscope and said platform for controlling said first prime mover, means responsive to relative movement of said second gyroscope and said platform for controlling said second prime mover, and means for maintaining the spin axes of said gyroscopes in a true vertical direction.

4. A master gyroscope system as in claim 3 in which said means for maintaining the spin axes of said gyroscopes in a true vertical direction comprises a pair of bails, means for pivoting said bails about axes extending parallel to the plane of said platform, and means for generating torque between said bails and said gyroscopes adapted to precess said gyroscopes to a position with their spin axes in a true vertical direction.

5. A master gyroscope system as in claim 3 in which said means for maintaining the spin axes of said gyroscopes in a true vertical direction comprises electromagnetic means for creating torque about the tilt axes of said gyroscopes, and means for supplying an erecting potential to said electromagnetic means whereby to process said gyroscopes to a position having their spin axes in a true vertical direction.

6. In a master gyroscope system, a platform, a gyroscope having a housing, a gyroscope Wheel mounted for rotation within said housin about a spin axis, means for pivotally mounting said housing for rotation about an axis parallel to the plane of the platform and extending at right angles to the spin axis of said gyroscope wheel, a bail, means for pivoting said bail about an axis extending at right angles to the axis of rotation of said gyroscope housing, means driven by said gyroscope wheel for creating a torque about the axis of rotation of said gyroscope housing through said bail whenever the plan of the bail extends at a position which is not in alignment with the true vertical direction, co-acting means carried by said platform and said bail for selectively immobilizing said bail, and means responsive to acceleration for actuating said coacting means to lock said bail.

7. In a master gyroscope system, a platform, a gyroscope having a housing, a gyroscope wheel mounted for rotation Within said housing about a spin axis, means for pivotally mounting said housing for rotation about an axis parallel to the plane of the platform and extending at right angles to the spin axis of said gyroscope Wheel, a bail, means for pivoting said bail about an axis extending at right angles to the axis of rotation of said gyroscope housing, means driven by said gyroscope wheel for creating a torqu about the axis of rotation of said gyroscope housing through said bail whenever th plane of the bail extends at a position which is not in alignment with the true vertical direction, co-acting means carried by said bai] and said platform respectively, adapted to selectively immobilize said bail, an electromagnet for operating said co-acting means to immobilize said bail, and means responsive to acceleration for controlling the energization of said electromagnet.

8. A master gyroscope system as in claim 7 in which said means responsiv to acceleration ineludes an inverted pendulum, centering springs tending to hold said pendulum in a vertical position, and means adapted to complete circuits through said electromagnet when said inverted pendulum moves against the action of said centering springs.

9. A master gyroscope system adapted to be carried by a rapidly maneuverable craft, including in combination a platform, a gyroscope having a housing, a gyroscope wheel mounted for rotation within the housing about a vertical spin axis, means for pivotally mounting the housing for rotation about an axis parallel to the plane of the platform and extending at right angles to the spin axis of the gyroscope wheel, an erecting means for maintaining the spin axis of the gyroscope in a vertical position, an armature carried by the housing, electromagnetic means adapted to influence the armature to create a torque about the axis of rotation of the yroscope housing, means for generating a potential having a desired characteristic, inertia means, means controllable by the inertia means for immobilizing the erecting means, circuit means for impressing the potential of desired characteristic upon the electromagnetic means to precess the gyroscope in accordance with the predetermined characteristic, and means responsive to the inertia means for rendering said circuit means operative simultaneously with the placing of the erectin means in inoperative condition.

CARL L. NORDEN. WILLIAM C. COULBOURN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,066,860 Sparmann July 8, 1913 1,236,993 Sperry et al Aug. 14, 1917 1,324,477 Tanner Dec. 9, 1919 1,501,886 Abbot July 15, 1924 1,627,178 Henry May 3, 1927 1,733,531 Dugan Oct. 29, 1929 2,188,606 Koster Jan. 30, 1940 2,238,645 Horn Apr. 15, 1941 2,315,167 Von Manteuffel et al. Mar. 30, 1943 2,342,637 Bechberger Feb. 29, 1944 2,411,087 Ford et al Nov. 12, 1946 2,412,481 Summers Dec. 10, 1946 2,417,573 Strother Mar. 18, 1947 2,423,270 Summers July 1, 1947 2,433,837 Dawson Jan. 6, 1948 FOREIGN PATENTS Number Country Date 374,175 Germany Apr. 30, 1923 425,034 Great Britain Mar. 4, 1935 544,756 Great Britain Apr. 27, 1942 

